The present invention relates to a pipe coupling for joining a first pipe to either a second pipe, a pipe elbow, a fitting, a machine or the like. In the coupling at least two half shells engage around the first pipe to form an axial gap, and the shells can be tightened against each other by radially-acting tightening means. The shells engage axially behind a coupling collar by means of a radially inwardly projecting annular shoulder, and together the shells and collar enclose a sealing ring which is supported on the pipe wall by a radially acting sealing surface and in the axial direction on the one side directly or indirectly by the coupling collar and on the other side by a support ring. The support ring is likewise enclosed by the half shells and is pushed loosely onto the first pipe. It is acted on in the axial direction by an inner cone of the half shells when the tightening means are tightened and thereby presses the sealing ring, which projects into a conical sealing chamber formed by the support ring, against the coupling collar.
An embodiment of this general type is disclosed in German Offenlegungsschrift (OS) No. 3,508,287. Various embodiments for pipe joints, fittings or machines are disclosed. A flange, a clamp element, and also a chamber part are pushed onto a pipe end that is to be butt-connected to a free pipe connection. The chamber part has a circular annular clamping chamber which is open toward the flange and into which the clamp element i pushed. The clamp element consists of a conical or convex disk supported with a radially internal clamping edge on the pipe wall and, with regard to its radially external clamping edge, having engaged over it an annular clamping surface of the clamping chamber. In the unloaded state, the clamp end projects out over the end face of the chamber part. The design of the clamping element is chosen here such that a force pressing the clamping element in an axial direction against the rear side of the clamping chamber leads to an increase in the external diameter, and simultaneously to a decrease in the internal diameter, of the clamping element. The chamber part is likewise provided with a sealing chamber respectively open toward the joint abutment and designed with a conical shape and thus tapered towards the neighboring flange. The joint abutment is enclosed by a seal, which is constructed as an elastomeric, shaped seal in which an inner ring is embedded. The external contour of the seal somewhat corresponds to that of the two sealing chambers but is overdimensioned, so that pressing together of the two chamber parts acts on the seal with a pressure directed axially and radially inwardly. In the embodiment according to FIG. 8 of this prior art document, the connecting means are formed by two half shells, which clampingly engage behind the two flanges. Here the flange on the pipe side has, on its side turned away from the chamber part, a conical shoulder against which abuts a correspondingly conically shaped strap of the half shells. Both half shells are provided with axial strap attachments, in order to be tightened against each other.